title: Behavioural responses and expression of P2X3 receptor in trigeminal ganglion after experimental tooth movement in rats.
abstract: OBJECTIVE
  To explore the role of P2X(3) receptor in pain induced by experimental tooth movement.
  
  
  METHODS
  Male Sprague-Dawley rats weighing 200-300g were used. P2X(3) receptor distribution in the caudal one-third portion of the trigeminal ganglion (TG) was studied by IHC. Next, the changes of P2X(3) expression were detected by Western blotting 4h, 1d, 2d, 3d, 5d, 7d, 14d after tooth movement. We then developed a behaviour pain model associated with directed mouth wiping. Finally, the effect of TNP-ATP on nociceptive-like behaviour was evaluated.
  
  
  RESULTS
  Our results showed that P2X(3) receptors were expressed mainly in small- and medium-sized cells and experimental tooth movement led to an increase in staining of mandibular P2X(3) receptors. In addition, following experimental tooth movement, the expression of P2X(3) receptor in TG was statistically significantly up-regulated from days 1 to 5, with a peak on day 3. It was also found that the time spent on directed mouth wiping was dramatically increased by experimental tooth movement from days 1 to 7. The rhythm change of P2X(3) receptor expression in TG and the mouth wiping behaviour were in concert with the initial orthodontic pain responses. The directed mouth wiping behaviour was modulated in a force-dependent manner and could be attenuated by peripheral and systemic morphine. Furthermore, peripherally administered TNP-ATP could exert an analgesic effect on this pain model.
  
  
  CONCLUSIONS
  These results suggest that directed mouth wiping behaviour can be a reliable measurement of pain following experimental tooth movement in rats. The P2X(3) receptor is important in the development and maintenance of tooth movement pain and thus may be peripheral targets for analgesics in orthodontic pain control.
authors.affiliation: State Key Laboratory of Oral Diseases and Department of Orthodontics, West China College of Stomatology, Sichuan University, Chengdu, China.
authors.forename: Zhi
authors.initials: Z
authors.lastname: Yang
authors.forename: Yang
authors.initials: Y
authors.lastname: Cao
authors.forename: Yan
authors.initials: Y
authors.lastname: Wang
authors.forename: Wei
authors.initials: W
authors.lastname: Luo
authors.forename: Xiaochuan
authors.initials: X
authors.lastname: Hua
authors.forename: Yun
authors.initials: Y
authors.lastname: Lu
authors.forename: Zhengyu
authors.initials: Z
authors.lastname: Liao
authors.forename: Wenli
authors.initials: W
authors.lastname: Lai
authors.forename: Zhihe
authors.initials: Z
authors.lastname: Zhao
mesh_terms: D000255:Adenosine Triphosphate / Q000008:administration & dosage / Q000031:analogs & derivatives; D000701:Analgesics, Opioid / Q000008:administration & dosage; D000818:Animals; D005456:Fluorescent Dyes / Q000008:administration & dosage; D015870:Gene Expression; D006120:Grooming / Q000502:physiology*; D008297:Male; D009020:Morphine / Q000008:administration & dosage; D017288:Pain Threshold; D058919:Purinergic P2 Receptor Antagonists; D051381:Rats; D017207:Rats, Sprague-Dawley; D018048:Receptors, Purinergic P2 / Q000032:analysis / Q000378:metabolism*; D058477:Receptors, Purinergic P2X3; D014087:Tooth Movement Techniques / Q000009:adverse effects; D014098:Toothache / Q000188:drug therapy / Q000503:physiopathology; D012668:Trigeminal Ganglion / Q000187:drug effects / Q000378:metabolism* / Q000503:physiopathology
chemical_list: D000701:Analgesics, Opioid; D005456:Fluorescent Dyes; D058919:Purinergic P2 Receptor Antagonists; D018048:Receptors, Purinergic P2; D058477:Receptors, Purinergic P2X3; C045674:2',3'-O-(2,4,6-trinitro-cyclohexadienylidine)adenosine 5'-triphosphate; D009020:Morphine; D000255:Adenosine Triphosphate